Life under an erratic single mom, first on welfare, then a millionaire, in the 1980s proved a wearying contest for survival of the fittest as recounted in this valiant, bittersweet debut by Danvers, Mass., native Ruta. Five feet tall and Italian American, with a loud gutter-mouth, copious breasts, and bleached blond hair, Kathi aka Mum lived from one menial job to the next that kept her comfortably supplied with pain killers she happily shared with her only daughter while concocting conflicting plans for her including school scholarships and early pregnancy. Ruta lived in the basement of her grandfather's house on Massachusetts's North Shore, surrounded by her mother's other Italian American relatives ("a band of lunatics" who enjoyed a "thuggish, moronic code of honor"), as she learned from hard experience to endure her mother's overbearing solicitude, such as when her mother sent 13-year-old Ruta to Catholic school on picture day dolled up like a trollop or traipsing through the most exclusive New England boarding schools seeking admittance. In fact, Kathi's hare-brained scheme worked, and Ruta was admitted to Phillips Academy Andover, where, to her mother's delight, her decidedly square daughter could finally catch up on sex and drugs. Fueled by profits from taking over her second husband's livery business, Kathi delved hard into heroin and other drugs, providing a titanic model for her daughter both to emulate and overcome. Survival required separation, and Ruta's account is a fairly dry, restrained chronicle of a wrenching embrace of health and sobriety. (Mar.)